The invention relates to method and system for controlling operation of an engine based on cylinder pressure.
Some internal combustion engines are designed to be used in hazardous or potentially hazardous environments, such as underground mining applications and offshore drilling applications. Typically, such engines are mechanically controlled. More specifically, fuel injections are controlled based on movement of a cam shaft. Furthermore, fuel injection timing for such engines is a function of engine load, and not engine speed. As a result, these engines are inefficient.
For non-hazardous environments, engines are typically controlled by an electronic control unit having volatile and non-volatile memory, input and output driver circuitry, and a processor capable of executing a stored instruction set. A particular electronic control unit communicates with numerous sensors, actuators, and other control units to control various functions of an engine and its associated systems. Such an electronic control unit, however, is not configured to be used in hazardous or potentially hazardous environments, and does not include a means for effectively controlling combustion in the engine.
The invention addresses the shortcomings of the prior art by providing an improved method and system for controlling engine operation, wherein the method and system are especially useful in hazardous or potentially hazardous environments. Furthermore, the method and system of the invention effectively control combustion in the engine.
Under the invention, a method for controlling operation of an engine having a cylinder includes sensing cylinder pressure; comparing the cylinder pressure to a pressure threshold; and adjusting an engine control parameter when the cylinder pressure exceeds the pressure threshold.
Advantageously, combustion in the engine may be effectively controlled by the method of the invention so as to allow the engine to operate in hazardous and potentially hazardous environments. Furthermore, the method allows the engine to continue operation when the pressure threshold is exceeded. Thus, an operator is provided time to respond to a situation, rather than having the engine abruptly shut down.
Adjusting an engine control parameter preferably includes reducing available engine torque. As a result, fuel supplied to the engine is reduced, but the engine may continue to operate. Other examples of adjusting an engine control parameter include advancing timing of a fuel injection to the engine, adjusting air supplied to the engine, adjusting exhaust gas re-circulation rate, and reducing engine loading.
The method may also include comparing the cylinder pressure to an additional pressure threshold, and shutting down the engine when the cylinder pressure exceeds the additional pressure threshold.
Further under the invention, a system for controlling engine operation includes a cylinder pressure sensor for sensing cylinder pressure, and a controller in communication with the cylinder pressure sensor. The controller includes control logic for comparing the cylinder pressure to a pressure threshold, and control logic for adjusting an engine control parameter when the cylinder pressure exceeds the pressure threshold.
A computer readable storage medium according to the invention is also provided. The computer readable storage medium has information stored thereon representing instructions executable by an engine controller that is in communication with a cylinder pressure sensor. The computer readable storage medium includes instructions for determining cylinder pressure based on signals provided by the cylinder pressure sensor; instructions for comparing the cylinder pressure to a pressure threshold; and instructions for adjusting an engine control parameter when the cylinder pressure exceeds the pressure threshold.
These and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.